What I meant above is that I was clicking on the Zamboni itself (not on an arrow), holding the mouse button down, and dragging.
Those steps seemed to work (although not consistently) to manipulate the Zamboni's motion.
[Have not dared to experiment further for fear that I will find myself spending far too much time enjoying this diversion. ]

(FYI for mods: I see that someone else later started a second Google thread in the Edge -- if you want to merge it with this first one started by CoyoteChris.)